This invention pertains to a system and method for locating faulty elements in a telephonic distribution system.
Telephonic distribution systems continue to expand at a rapid rate and increasingly the designs of such systems are hierarchical with many subtended branches. Such systems are used for transmitting combined video and telephone signals via a fiber/coaxial cable and are connected to system elements such as launch amplifiers, extender amplifiers, bridge amplifiers, tap amplifiers and customer premise equipment. Such a system is disclosed in "Combining Apples and Oranges, The Fiber/Coax Network: parts 1-4, Telephony, Jan. 24, 1994, Feb. 7, 1994, Feb. 21, 1994 and Mar., 7, 1994, "Hybrid Fiber-Coax Access Networks" Bell Labs Technical Journal Volume 1, Number 1, Summer 1996 and "Generic Requirements and Objectives for Fiber in the Loop Systems" Bell Communications Research Inc., Technical Reference TRNWT-000909, the disclosures of which are incorporated by reference.
Existing tests and procedures for locating faults in a telephonic distribution system are run at off-hours, typically between 12:00 a.m. and 2:00 a.m., when call activity in the telephonic distribution system is at a minimum. In addition to the disadvantage of running the test at off-hours, certain tests, e.g. a channel and drop test, require that the line connection at customer premise equipment (CPE) be disconnected resulting in the disconnection of service to the customer while the test is being conducted.
A CPE is equipment located at the end customer. The channel and drop test only determines whether a fault exists in the CPE or in the telephone network upstream of the CPE. To locate a fault using the channel and drop test, an analysis is performed beginning at the customer premise equipment (CPE) and working back toward a central office to find the location of the fault. This results in potential lost revenue and other problems associated with discontinuity of service to the customer. Accordingly, the channel and drop test is not suited for repetitive operation during business hours.
Furthermore, tests such as the channel and drop test provide less meaningful information for the locations of faults when used on telephonic distribution systems having a hierarchical design with numerous subtending branches because the identity of an upstream element causing the fault is not easily discerned in such telephonic distribution systems. Upstream elements are upstream of the CPE and downstream from the central office.
The present invention is directed to overcoming, or at least reducing, the effects of one or more of the problems set forth above.